It will make available to the public 2.4M records, including historical images, audio and video

The new National Digital Public Library will initially contain 2.4 million digital records, including historical images, video and audio that had previously been siloed in public and private institutions.

The Digital Public Library of America (DPLA) today launched a beta of its discovery portal and open platform.

Two years in the making, the DLPA will make available to the public 2.4 million records at its launch, including electronic images, video and audio from America's libraries, archives and museums. It also makes many scientific records available.

"You will find gems that include daguerreotypes of ... former [President] Abraham Lincoln, images of women marching for the vote in Kentucky, news film clips of the Freedom Riders during the Civil Rights movement, The Book of Hours, an illuminated manuscript from 1514, Notes on the State of Virginia, written by Thomas Jefferson, and paintings by Winslow Homer," Emily Gore, DPLA Director for Content said in a statement.

The portal contains materials found in American archives, libraries, museums and cultural heritage institutions. The portal provides various ways to search and scan through its collection of distributed resources. Special features include a dynamic map, a timeline that allow users to visually browse by year or decade, and an app library that provides access to applications and tools created by external developers using DPLA's open data.

"The wonder and joy of entering an expansive library for the first time is truly a special feeling. We are delighted to be able to share this unified, open collection with Americans and the world, and can't wait to see what people discover, and what new applications and knowledge will be created," Dan Cohen, executive director of the DPLA, said in a statement.

While many universities, public libraries, and other public and private organizations have digitized materials, they are often digital collections that exist in silos.

In December 2010, the Berkman Center for Internet & Society at Harvard University, along with the the Alfred P. Sloan Foundation, hosted a conference of leading experts in libraries, technology, law and education to begin work on the digital library project.

In October 2011, the Berkman Center hosted hundreds of public and research librarians, technical innovators, digital humanists, and other volunteers who formed six work teams to map out the scope, design, and construct the DPLA.

The DPLA portal is powered by a rich repository of information, known as the DPLA platform, and uses an open API that can be used by software developers, researchers and others to create novel environments for learning, tools for discovery and engaging apps.

"The DPLA's goal is to bring the entire nation's rich cultural collections off the shelves and into the innovative environment of the Internet for people to discover, download, remix, reuse and build on in ways we haven't yet begun to imagine," Maura Marx, director of the DPLA Secretariat, said in a statement. "Regular users can search in the traditional way using the portal, and developers and innovators can build on big chunks of code and content using the platform -- we're creating access, not controlling it."

From the Digital Public Librarys exhibition page: A view of unidentified men protesting segregated facilities outside of Rich's store in downtown Atlanta, Ga., in December 1960.